Many police cars now include a video camera to capture activities transpiring both outside and inside the vehicle. One use of the video captured by these cameras is as evidence in a criminal trial. In order for the videos to be used as evidence, the images must be clearly identifiable by, for example, a jury or an expert witness. Often police cars and their corresponding devices for recording video data may remain in use for extended periods of time, for example, when an officer stays out on patrol overnight. It is often necessary to compress the video being recorded in order to be able to store those large volumes of data.
In order to store the large amount of data captured by the video camera over long periods of time, compression algorithms are normally used to compress the data. There are various compression algorithms currently in use for compressing videos, such as lossless and lossy algorithms. In a lossy algorithm, some visual quality is lost in the compression process and cannot be restored. The various compression algorithms utilize a combination of techniques for compressing the data such as downsampling or subsampling, block splitting, pixilating, and lowering resolution. A few examples of compression algorithms include the MPEG family of algorithms such as MPEG 2 and MPEG 4.